The disclosure relates to a method for determining the functional capability of a brake system which has at least one wheel brake with a movable brake piston, a hydraulic pressure generator for setting a first braking force which acts on the brake piston, and an electromechanical actuator for setting a second braking force which acts on the brake piston, wherein in order to set a parking braking force at the wheel brake the hydraulic pressure generator and the actuator are actuated.
Furthermore, the disclosure relates to a device for executing the method and to a corresponding brake system.
Methods, devices and brake systems of the type mentioned in the introduction are known from the prior art. Wheel brakes which can be actuated both hydraulically and electromechanically are usually used to set a braking force hydraulically during the normal operation of the motor vehicle and electromechanically for the implementation of a parking brake function (parking brake). The advantage here is that the electromechanical activation of the brake system, which is otherwise activated hydraulically, makes possible a particularly compact configuration of a hydraulic wheel brake with an electromechanical parking brake integrated therein. Owing to the self-locking which is usually provided for the electromechanical actuator, the latter holds the brake piston in the parking brake position even when the hydraulic pressure is reduced again. This ensures that the parking braking force is maintained in an energy-saving and simple fashion. In order to set the parking brake function or the parking braking force, the brake piston is activated both hydraulically and electromechanically, so as to relieve the loading on the electromechanical actuator during the setting of the parking braking force.